Modern MIMO radar systems are used in a variety of applications, such as telecommunications, automobile applications, and the like. The aperture size of a MIMO radar system is a significant factor that affects angular resolution and the number of channels in the aperture. The distance between each adjacent channel pair is also a factor of angular ambiguity.
In order to reduce overall system costs, it is preferable to design a MIMO radar system with a limited antenna area and a limited number of transmit (“TX”) channels and receive (“RX”) channels. Conventional radar aperture design, including traditional single-input-multiple-output (“SIMO”) radar systems and MIMO radar systems, use a half wavelength for a two-way channel-to-channel distance. The overall radar aperture size of an N-channel radar can be (N−1)*λ/2, or N*λ/2 if the antenna patch area is included.
In order to increase angular resolution, some MIMO radar systems are using antenna structures with a channel-to-channel distance larger than λ/2 or half-wavelength. However, such MIMO radar systems can suffer from worsened angular ambiguity performance caused by grating lobes in the antenna pattern.